thetyreman
Established Member
I've ordered a 1/4" collet, will see if that fixes the problem when it arrives.
power router problems
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J-G
Established Member
I suggest that 'works' ought to be taken with a large pinch of salt - sorry.
An 'ER' type collet closes [parallel] over its range but simple draw-bar or closing nut actuated collets just squeeze the nominal size. Over a few thou this is not a problem but you will surely see from my sketch that at 20mm out from the mouth of the collet a 6mm cutter in a ¼" collet will potentially 'wobble' up to 10% of the nominal diameter.
That is assuming that there is sufficient travel in the closing mechanism to actually 'close' the collet. You will also observe that the clamping is at a single point (ring) with all that implies.
I'm not saying that you can't hold cutters smaller than the nominal collet size, but that doing so will not give you the security or accuracy that can normally be expected.
Going the other way - trying to force a ¼" cutter into a 6mm collet - whilst maybe not impossible with a worn collet - would have similar (though different) issues. This is what I suspect is the problem for the @thetyreman
Sgian Dubh
Established Member
My first thought is that you've got the router set up so that you'd naturally put your right hand on the trigger handled side of the tool, i.e., the router handle on the opposite side to where the fence is sticking out. That makes me wonder if you pushed the router from right to left to make the cut, i.e., away from end where the camera is located which would be a climb cut. If that's what you did the cutter would have tended to push the side fence away from the edge of the timber if the router's fence is not very firmly held by the user tight to the wood. Any such drifting of the fence would result in a wavy, curved or stepped edge to your groove on the side nearest the fence. Unless my eyes are deceiving me I'm fairly sure I see evidence of such deviation and steps and that would explain the groove being wider than the diameter of the cutter.
To make that cut accurately to match the cutter's diameter with the router set up as it is you should pull the router towards you starting at the far end, away from the camera, and working to the end of the groove nearest the camera, in other words you should make the cut from left to right, which is a normal cut. That way, notwithstanding any comments about how much of the cutter's shank is engaged with the collet, the action of the cutter in use is to pull the side fence tight against the edge of the piece of wood.
On a side note, if the cutter's not properly engaged in the collet and sticks out at an odd angle, or the collet or cutter is describing some sort of eccentric rotation and you find that, for example, a 6mm diameter cutter somehow cuts a groove that's greater than 6 mm, I'd expect to hear, see, feel or in some other way that something was seriously wrong, such as the cutter dropping out of the collet or excessive vibration.
Finally, some people prefer to pull the router towards them to cut grooves, mouldings, rebates, and the like, and your set up suits that method of operation. I tend to prefer pushing the router whenever I can and if I was setting up to make that cut I would put the side fence so that it was sticking out to the other side to your set up so that fence is on the same side as the triggered handle which better suits a pushing method of operation. Slainte.
To make that cut accurately to match the cutter's diameter with the router set up as it is you should pull the router towards you starting at the far end, away from the camera, and working to the end of the groove nearest the camera, in other words you should make the cut from left to right, which is a normal cut. That way, notwithstanding any comments about how much of the cutter's shank is engaged with the collet, the action of the cutter in use is to pull the side fence tight against the edge of the piece of wood.
On a side note, if the cutter's not properly engaged in the collet and sticks out at an odd angle, or the collet or cutter is describing some sort of eccentric rotation and you find that, for example, a 6mm diameter cutter somehow cuts a groove that's greater than 6 mm, I'd expect to hear, see, feel or in some other way that something was seriously wrong, such as the cutter dropping out of the collet or excessive vibration.
Finally, some people prefer to pull the router towards them to cut grooves, mouldings, rebates, and the like, and your set up suits that method of operation. I tend to prefer pushing the router whenever I can and if I was setting up to make that cut I would put the side fence so that it was sticking out to the other side to your set up so that fence is on the same side as the triggered handle which better suits a pushing method of operation. Slainte.
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That's why I wondered if the deviation was uniform along the length.
worn thumbs
Established Member
J-G
Established Member
Though not an ER type, that IS a parallel closing collet so does have a 'range' that could well cover 6mm & ¼"
J-G
Established Member
I was actually just addressng the basic principle and hadn't looked that closely at the original photo's, but yes, the further 'out' the cutter is the larger will be the size error.
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Chief Sawdust Maker
Darren
I would suggest that cutter not deep enough in collet, collet incorrect size and cutter being single flute
All of the above as previously mentioned will add a percentage to being inaccurate
If the need for the slot is regular perhaps a table or jig would help
D
All of the above as previously mentioned will add a percentage to being inaccurate
If the need for the slot is regular perhaps a table or jig would help
D
Hi thetyreman. When the collet arrives to suit your 1/4" shaft diameter router bit the cutter needs to inserted in the collet at least 75% of the shaft length. A "rule of thumb" for handheld routing suggests the depth of cut for each pass should be around 50% of the cutter diameter.
It is very convenient to form grooves with a straight cutter using a hand-held router. That is why, we all do it. But it isn't ideal as you don't always get the accuracy you would hope for
Obviously, the OP has just one simple groove to machine and in his particular case it seems - more likely than not - that it will turn out to be the fit in the collet that is the problem. However, some 1'2" routers can be a bit of 'beast' to control and keep on course - and, achieving multiple, accurate cuts can often be problematic.
If possible, I much prefer cutting grooves using a wing cutter. It's a lot more satisfactory and easier to control. This has its limitations as well, re the distance in from the edge, but I find it gives better results. I found this out when trying to fit Tonks/ Library strip, using a straight-cutter and failing miserably.
Obviously, the OP has just one simple groove to machine and in his particular case it seems - more likely than not - that it will turn out to be the fit in the collet that is the problem. However, some 1'2" routers can be a bit of 'beast' to control and keep on course - and, achieving multiple, accurate cuts can often be problematic.
If possible, I much prefer cutting grooves using a wing cutter. It's a lot more satisfactory and easier to control. This has its limitations as well, re the distance in from the edge, but I find it gives better results. I found this out when trying to fit Tonks/ Library strip, using a straight-cutter and failing miserably.
A dado cutter in a tablesaw is the ideal tooling for this kind of work. I've used one for thirty years without any problems whatsoever.
HamsterJam
Let’s take it apart to see what’s inside….
Coincidentally, I have been routing slots today. Accuracy isn’t an issue for my particular application but even so I didn’t rely on the router fence to keep me straight.
Instead I made a slotted jig from a ply offcut and followed that with a guide bush, making multiple passes cutting a couple mm deeper on each one until I got close to my required depth then finishing with a light cut (probably 0.5mm).
Instead I made a slotted jig from a ply offcut and followed that with a guide bush, making multiple passes cutting a couple mm deeper on each one until I got close to my required depth then finishing with a light cut (probably 0.5mm).
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For running the type of groove you are doing I have two side fences which keep the router centralised and more stable also plunge cutting mortice holes are much easier to do
Also when zooming in on your first photo I notice the cutter is a downward cut spiral which must be two flutes surely
thetyreman
Established Member
well spotted, yes because the truss rod I am installing is not a normal one, it has a rounded bottom not flat, the truss rod is a spoke wheel type and a bit more complicated to install than a regular one.
Distinterior
Established Member
It is a twin flute cutter,...But, it's not a downward cut @thetyreman !
I use upcut, downcut and compression solid carbide cutters, some of which I've bought from Wealden and the 3rd picture that Thingybob posted in his #9 post, is an uncut spiral.
Sgian Dubh
Established Member
I'm somewhat surprised this debate is ongoing. The original post stated that the 1/4" (~6.3 mm) diameter router bit resulted in a groove about 10 mm wide. In other words, the router bit was cutting a groove roughly 3.7 mm wider than the bit's diameter.
If there was that amount of flexing in the bit in use caused by, for example, not enough of the shank engaged in the collet I'd expect to hear at least some unpleasant sounds, and more than likely the bit would either break or fall out of the collet pretty quickly, the latter being something that's happened to me (only once!) when I've been pushing the boat out with bit extrusion when seeking more depth of cut than I knew was sensible.
If the bit isn't held correctly in the collet so that it sticks out at a funny angle, an angle that would be enough for a 6.3 mm diameter bit to cut a 10 mm wide groove, the centre point at the end of the bit when spinning would surely be describing a circle with the cutting edges of the bit describing a circle with a 10 mm diameter. That's analogous to a rope with a weight at the bottom suspended on a hook that's pushed to rotate rather swing back and forth in the same plane. Again if that's the case and with that much eccentricity in the spinning of the bit, and I'm not doubting that bits can protrude from the collet very slightly out of line with the rotational axis, I think I'd expect to be aware that something isn't right as soon as I turned on the router, e.g., vibration, perhaps a funny noise from the motor, and feedback at the point of engaging the cutter with the wood would send some sort of message that something's amiss.
Maybe I'm all wet on this, but I still suspect the problem may be something to do with improper control of the router including use of the side fence, e.g., climb cutting and not holding the fence tightly along the edge of the wood, the fence not locked properly, or something I haven't thought about.
Setting up a single side fence on a router and using it to set the distance in from the edge of a piece of wood that a cut is made is a common and fundamental operation: I must admit I'm a little surprised to see a few comments alluding to how tricky or uncontrollable some seem to find the job along with one or two descriptions of finding alternative set ups to get the same or similar results. Perhaps I've been around routers so long and that I'm pretty familiar with their set up and use and I've rather forgotten how tricky, or perhaps daunting, they can be if both limited experience and confidence is/are an issue. Slainte.
If there was that amount of flexing in the bit in use caused by, for example, not enough of the shank engaged in the collet I'd expect to hear at least some unpleasant sounds, and more than likely the bit would either break or fall out of the collet pretty quickly, the latter being something that's happened to me (only once!) when I've been pushing the boat out with bit extrusion when seeking more depth of cut than I knew was sensible.
If the bit isn't held correctly in the collet so that it sticks out at a funny angle, an angle that would be enough for a 6.3 mm diameter bit to cut a 10 mm wide groove, the centre point at the end of the bit when spinning would surely be describing a circle with the cutting edges of the bit describing a circle with a 10 mm diameter. That's analogous to a rope with a weight at the bottom suspended on a hook that's pushed to rotate rather swing back and forth in the same plane. Again if that's the case and with that much eccentricity in the spinning of the bit, and I'm not doubting that bits can protrude from the collet very slightly out of line with the rotational axis, I think I'd expect to be aware that something isn't right as soon as I turned on the router, e.g., vibration, perhaps a funny noise from the motor, and feedback at the point of engaging the cutter with the wood would send some sort of message that something's amiss.
Maybe I'm all wet on this, but I still suspect the problem may be something to do with improper control of the router including use of the side fence, e.g., climb cutting and not holding the fence tightly along the edge of the wood, the fence not locked properly, or something I haven't thought about.
Setting up a single side fence on a router and using it to set the distance in from the edge of a piece of wood that a cut is made is a common and fundamental operation: I must admit I'm a little surprised to see a few comments alluding to how tricky or uncontrollable some seem to find the job along with one or two descriptions of finding alternative set ups to get the same or similar results. Perhaps I've been around routers so long and that I'm pretty familiar with their set up and use and I've rather forgotten how tricky, or perhaps daunting, they can be if both limited experience and confidence is/are an issue. Slainte.
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thetyreman
Established Member
fixed now! it was the wrong size collet, works very well now with no weird vibrations, also sounds better bit like a well running engine, thanks for all the help and advice, I can get back to routing now with confidence.
